Synchronous & Asynchronous Transmission

Synchronous & Asynchronous Transmission

Introduction:

In this blog post, I will be explaining about what synchronous and asynchronous transmission are and what they do; I will also provide examples of each and identify limitations that are relevant when explaining the content.

In general, both of these transmissions are there to determine how data are sent overall. What makes these transmissions different from each other and how fast data is sent all depends on whether they have clocking signals or no clocking signals (synchronisation). Clocks are essentially a speed rate of how many bits are sent at a set time - they are both serial (where one byte is sent right after another).

Synchronous Transmission:

Synchronous transmission is a method where both the sender and recipient devices are synchronised, this means that data sent are sent at regular intervals and must be both online on the internet for information to be sent and communicated. Furthermore, this makes it reliable because the flow of data is sent at a considerable rate – usually set by what is known as a clock that uses clocking signal.

An example of this would be voice to voice channels on Skype – where two users must be online and in a call for them to be able to communicate. Another example would be a DCE such as “a router, WAP or switch” or even modems due to its functionality on bandwidths because it usually sends multiple bytes at one time (the DCE allows the clocking signal to be more rapidly).

However, the limitations of synchronous is that this transmission method needs requires both sides to be available or otherwise it will not work – one person may be busy or could be around the world with a different time zone overall and this can make it extremely inconvenient and unreliable. Lastly, for synchronous transmission to take place, it will be at a higher cost.

Asynchronous Transmission:

Hence the ‘A’ in front of the word it means that it is unlike synchronous transmission. Whereas synchronous uses clocking signals, asynchronous does not and instead sends data whenever by using a “start bit and stop bit” (www.computerhope.com/, 2015) that informs the device when to start sending and when to stop. An example of this transmission method is emails sent from the client to the recipient. The recipient does not have to be available but however the email will still arrive to the inbox successfully and can be replied at any time – not required both parties to be synchronised.

On the other hand, one limitation to this is that it requires the other recipient device to give an acknowledgement (confirmation) that it can then send data, relating to slower speed. Another common example such as computer to a printer (serial) would be asynchronous due to having a one way system. Despite all these limitations, one benefit would be its low cost.

Harvard Referencing: (In order of reference)
- Anderson, K. Atkinson-Beaumont, D.Kaye, A. Lawson, J. McGill, R. Phillips, J and Richardson, D. 2011. Information Technology Level 3 Book 1 BTEC National. Harlow: Pearson Education Limited.
- computerhope, 2015. Asynchronous. [Online] Available at: <http://www.computerhope.com/jargon/a/asynchro.htm> [Accessed 31 January 2015].

Bibliography: (In alphabetical order)
- sites.google, n.d. Discuss the advantages and disadvantages of synchronous and asynchronous transmission. [Online] Available at: <https://sites.google.com/site/assignmentssolved/mca/semester3/mc0075/13> [Accessed 31 January 2015].